Isolate of trichoderma fungicidal compositions containing said isolate and use against b. cinerea and s. sclerotiorum

ABSTRACT

The present invention relates to a novel biologically pure culture of Trichoderma Harzianum, T-39, to biological control compositions containing same and to methods of protecting plants from the disease gray mold, caused by B. Cinerea and the disease white rot caused by S. Sclerotiorum with such compositions.

BACKGROUND OF THE INVENTION

The present invention relates to antifungal compositions, particularlyto biological control compositions containing Trichoderma harzianum andto methods of protecting plants from pathogenic fungi Botrytis cinereaand Sclerotinia sclerotiorum with such compositions.

Gray mold, incited by Botrytis cinerea Pers. Fr.; and white rot incitedby Sclerotinia sclerotiorum Lib: de Bary are serious problems in manycrops around the world. The pathogen attacks many crops includinggrapes, vegetables and ornamentals. Crops are attacked when grown in theopen or in structures under cover. If not adequately controlled, graymold and white rot can cause substantial pre-harvest as well aspost-harvest losses at storage and transport. The pathogens attack allparts of the plants including flowers, fruits, leaves, stems, branches,phyloclades, bulbs or seeds.

Chemical fungicides are widely used to control the disease. However, B.cinerea has developed resistance to common fungicides used. Among theseare dicarboxyimide fungicides and benzimidazole fungicides. In manyplaces, farmers do not have any solution for the problem because ofresistance and in other places or crops this is likely to happen in thefuture.

Gray mold and white rot epidemics are usually severe when high humidity,temperatures between 10° C.-25° C. and wetness over the sensitive organsof the plant prevail.

The use of antagonisitic micro-organisms in controlling plant pathogenicfungi has been the subject of extensive research. One of the mostfrequently studied antagonists in relation to biological control is thegenus Trichoderma (Y. Elad et al., 1982, Can. J. Microbiol. 28: 719-725;I. Chet and R. Baker, 1981, Phytopathology 71:286-290; M. N. Schroth andJ. G. Hancock, 1981, Ann. Rev. Microbiology 35: 459-463; Y. Elad et al.,1981, Plant Disease 65: 675-677; Y. Elad et al., 1980, Phytopathology70: 119-121; I. Chet et al., 1979, in B. Scrippers and W. Gams. eds.,Soil Borne Plant Pathogens", Academic Press, N.Y., N.Y.; Y. Hadar etal., 1979, Phytopathology 69: 64-68; C. Dennis and J. Webster, 1971,Trans. Br. mycol. Soc. 57 (3), 363-369: Y. Elad., (1990)Phytoparasitica, 18:99-105).

Species of strains of Trichoderma may be differentially antagonistic todifferent species of fungi (H. D. Wells et al., 1972, Phytopathology 62:442-447). Such differences in antagonism have been found both within andbetween species of Trichoderma (D. K. Bell et al., 1982, Phytopathology72: 379-382). Therefore each isolate of Trichoderma, regardless of itsspecies, has different features in abilities to contract plant diseases.

B. cinerea and S. sclerotiorum are sensitive to antagonism bycompetition of other microorganisms. Germination of spores and growth ofhyphae of this plant pathogen and infection of host plants can bereduced when nutrients and space are limited. Such a mechanism can be abasis for successful biological control of gray mold and white rot.More-over, the antagonist should be able to survive in the same nichefor a long time and be active against the pathogen at the same time.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a novelstrain of the species T. harzianum has been discovered, which is activeagainst the plant pathogens Botrytis cinerea and Sclerotiniasclerotiorum. The antagonist is useful in controlling the plant diseasegray mold which is caused by B. cinerea and white rot caused by S.sclerotiorum. The strain of T. harzianum T-39 (I-952) has been culturedin a biologically pure culture.

T. harzianum T-39 (I-952) can be applied on the canopy of plants alone,in tank mix and in alternation with the different fungicides used forcontrolling gray mold. The novel strain of T. harzianum can be grown,maintained and be mixed with a suitable agriculturally acceptablecarrier to produce a fungicidally active biocontrol composition usefulin controlling diseases caused by B. cinerea, and S. scleotiorum. Thebiocontrol composition may also contain a food base for the mycoparasiteof the carrier itself may also serve as a food base.

In one of the embodiments of the invention, the biocontrol compositionmay also contain a suitable agriculturally acceptable adhesive. Thebiocontrol agent T. harzianum T-39 (I-952) reduces disease caused by B.cinerea and S. sclerotiorum by 50%-90% as compared with non-treatedcontrols. The antagonist is capable of maintaining high population overleaves and fruits of the treated plants in greenhouses, vineyards orelsewhere. T. harzianum T-39 (I-952) is capable of competing with thefungus B. cinerea and S. sclerotiorum for nutrients and space. Thisgives this isolate its unique ability to control the disease.

The invention also concerns methods of using this biocontrol compositionas a fungicide against gray mold. Effective amounts of the biocontrolcomposition are applied to various parts of the plant.

In a specific embodiment of the invention, a chemical fungicide isincluded in the biocontrol composition. T. harzianum T-39 (I-952)possesses resistance to chemical fungicides which would kill or retardthe growth of other fungi. Resistance to such chemical antagonistsenables the invention to be used in integrated chemical and biologicalcontrol of B. cinerea and S. sclerotiorum. Alternatively, the chemicalfungicide is applied along either prior to or after treating with T.harzianum T-39 (I-952).

DETAILED DESCRIPTION OF THE INVENTION

A novel antagonistic strain of the species Trichoderma harzianum hasbeen discovered which is active against the plant pathogenic fungusBotrytis cinerea. The preferred strain of this novel antagonist wasisolated from the natural microflora of the phyloplane of cucumberfruit. The antagonistic fungus was cultured in biologically pure form,tagged as T-39 and identified according to the creteria of Rifai (Rifai,M., Mycol. Pap. 116). This preferred strain of Trichoderma harzianumRifai T-39 is deposited with Institute Pasteur, Collection Nationale deCultures de Microorganisms, Paris, France, pursuant to the provisions ofthe Budapest Treaty on the International Recognition of the Deposit ofMicroorganisms for the Purpose of Patent procedure under accessionnumber I-952.

T. harzianum Rifai T-39 (I-952) and the mutant derived therefrom may beused to control gray mold caused by B. cinerea and white rot caused byS. sclerotiorum. In addition to antagonistic ability, T. harzianum T-39(I-952) has long term survivability on the canopy of plants. It can beapplied on plants in alteration with fungicides which are aimed againstgray mold--examples are benomyl, carbendazim, vinclozolin, iprodione,procymidon, dichlorfluanide, tebuconazole, prochloraz, fenethanil,diethefencarb, metomeclan, chlorothalonil, and mixtures of thesefungicides.

T. harzianum T-39 (I-952) possesses resistance to the followingpesticides with which it may be applied on plants in variousagrosystems: polyoxin D, polyoxin B, TMTD, CuSO₄.5H₂ O diphenylamine,folpet, tridemorph, bitertanol, dimethirimol, triforine, dichloronit,roaniline, bupirimate, hexaconazole, miclobutanil, fenitrothion,phosethyl-Al, propiconazole, azinphos-methyl, chlorpyrifos, mancozeb,endosulfan, methomyl, tridimefon, quinomethionate, diniconazole,methidathian copper oxychloride, imazalil, oxadixyl, cymoxanil,metalaxil, triadimenol, ditalimfos, sulphur, and penoconazole.

In addition to its wide range of antagonism and resistance to chemicalfungicides and pesticides, T. harzianum T-39 (I-952) is capable of longterm survivability and of controlling gray mold and white rot throughouta 3° C. to 30° C. temperature range. This additional characteristicmakes the present invention a versatile biocontrol agent suitable forapplication a semi-arid as well as temperate agricultural zones, ingreenhouses or in the open, in storage or transportation of agriculturalproducts.

Methods of application of T. harzianum T-39 (I-952) are by means ofconidia, chlamydospores, or hyphal segments, or by means of eachcombination of them, directly to the canopy of the plants. Directapplication of the antagonist, however, seems to be less effective thanthe application of a biocontrol composition which contains T. harzianumT-39 (I-952) and an agriculturally acceptable carrier.

These biocontrol compositions may be in a solid or liquid form and mayinclude other adjuvants such as emulsifiers, suspending agents, stickingagents, etc. The solid compositions may be in the form of dusts,granules or wettable powders, whereas the liquid compositions may be inthe form of aqueous or non-aqueous media, in solutions, suspensions,dispersions, dispensions, or concentrate form.

The quantity of spores, hyphae, or chlamydospores of the antagonist inthe composition should be at least 10⁵ cells per gram of composition.Propagation of these spores depends upon growth conditions within thecomposition or on the plants on which it is applied. Such factors as thestorage time of the composition may have an effect on the growthconditions of the antagonist and therefore it is prepared in acomposition which contains a suitable food base.

In certain embodiments of the invention, the carrier may constitutewholly or in part a food base for the antagonist. The food base andcarrier provide the antagonist with sufficient nutrients and a favorablemicro-environment facilitating its establishment and long-termmicro-environment and long term survival on plant organs.

In other embodiments of the invention the biocontrol compositions mayalso contain another pesticide or another biocontrol agent such asanother isolate of an antagonistic microorganisms such as Trichoderma oranother species of microorganism.

For application on plants the biocontrol composition is applied at therate of 10-1000 grams in 10-300 ml water for 1000 m² of crop, or at therate of 0.05-0.05% w/w of water on pre-and post-harvested agriculturalproducts.

The range of host plants that are subject to attack by B. cinera or S.sclerotiorum is very broad. This invention is effective in controllingdiseases caused by this plant pathogen over this wide range and iseffective in protecting such plants as cucumber, tomato, pepper, grape,rose, strawberry, eggplant, bean, geranium, lettuce, carrots and otherplants.

While the invention will now be described in connection with certainpreferred embodiments in the following examples, it will be understoodthat it is not intended to limit the invention to these particularembodiments. On the contrary, it is intended to cover all alternatives,modifications and equivalents as may be included within the scope of theinvention as defined by the appended claims. Thus the following exampleswhich include preferred embodiments, will serve to illustrate thepractice of this invention, it being understood that the particularsshown are by way of example and for purposes of illustrative discussionof preferred embodiments of the present invention only and are presentedin the cause of providing what is believed to be the most useful andreadily understood description of procedures as well as the principlesand conceptual aspects of the invention.

EXAMPLE 1

A strain Trichoderma species was isolated from cucumber fruit asfollows:

Fruits were shaken in water at 200 rpm. Portions of the wash water werediluted one time and 0.1 ml was spread on selective medium agar plates(Elad et al., Phytoparasitica, 1981, Vol. 9, pp. 59-67). The resultantpure strain was named T-39. The isolate T-39 was identified according tothe key suggested by Rifai (Rifai, M., 1969, Mycol., Pap. 116) asTrichoderma harzianum.

EXAMPLE 2

T. harzianum T-39 (I-952) was grown on a solid state medium based onstarch as a major food source and celite as a water reservoir. Thegrowth starts by inoculating the solid medium with Trichoderma. Themixture of all the food ingredients, the celite, and the inocular aregranulated and are then incubated in a room kept at 25° C. During the 10days of the growth the medium is turned over twice and then dried andground. The end product contains 5×10⁹ to 1×10¹⁰ colony forming units(CFU) per gram. Viability tests showed that an initial 8.5×at least 10⁹CFU/g dry weight kept at room temperature for six months changed onlyslightly to 7.5×10⁹ CFU/g dry weight and after 12 months to 7×10⁸ CFU/gdry weight.

EXAMPLE 3

T. harzianum T-39 (I-952) was tested in growth medium (potato dextroseagar) amended with various fungicides and pesticides. Germination ofconidia was evaluated 24 hours after inoculation. In addition, thegrowth of mycelium within 3-4 days after inoculation at 20±2° C. wasalso evaluated. Pesticides were arranged in groups according to theirability to inhibit T. harzianum T-39 (I-952) (in Tables 1 and 2.

EXAMPLE 4

Conidia of Trichoderma spp. isolates were sprayed on various plants.Inoculation of the treated plants with B. cinerea was carried outthereafter. All treatments were incubated in a dew chamber at 16±2° C.to develop gray mold. Disease incidence was evaluated within 5 to 10days. The percentage of disease incidence by the various isolates ofTrichoderma spp. is presented in Table 3. The results show that T.harzianum T-39 (I-952)is far superior to the other isolates.

EXAMPLE 5

The effect of T. harzianum T-39 (T-952) against gray mold of grapes wastested by spraying in vineyards alone, as a composition with Iprodione,or alternatively with Iprodione in three different locations accordingto the recommended program in each region. The percent berries infectedis presented in Table 4. The results show improved control of thedisease when using T. harzianum T-39 (I-952).

EXAMPLE 6

T. harzianum T-39 (I-952) was sprayed on rose plants kept in acommercial heated greenhouse kept at 15° C.±3° C. and naturally investedwith B. cinerea and compared with the effect of a mixture oftebuconazole and dichlofluanide. The active biocontrol agents weresprayed at a volume of 1000 l/ha in water. Plots of 5 m×1 m wererandomized scattered in 5 replicates. Table 5 shows that T. harzianumT-39 (I-952) effectively controls stem infections of B. cinerea whenapplied alone or alternately with a mixture of tebuconazole anddiclofluanid.

EXAMPLE 7

Conidia of T. harzianum T-39 (I-952) were sprayed on cut rose flowersnaturally infected with B. cinerea. Flowers were incubated in a humiditychamber for six days and the severity of the gray mold was thenexamined. As shown in Table 6, a spray containing 10⁷ conidia per ml ismore useful for the biocontrol of rose gray mold.

EXAMPLE 8

Compositions of T. harzianum T-39 (I-952) in 1000 l/ha in water weresprayed alone, in conjunction with, or alternatively with chemicalfungicides on table grapes in vineyards naturally infested with graymold caused by B. cinerea. The infection was monitored on the bunches inthe vineyards, or on harvested bunches during incubation in a mistchamber. The results as shown in Table 7 shows, that T. harzianum T-39(I-952) effectively controls gray mold in table grapes applied invarious ways.

EXAMPLE 9

Compositions of T. harzianum T-39 (I-952) in a volume of 1000 l/ha weresprayed on tomatoes in a greenhouse. Plots consisted of 20 plantsrandomized in five replicates. Naturally occurring B. cinerea wasmonitored on stems, leaves and fruit. Symptoms on the fruits were eitherregular rot or ghost spots. As shown in Table 8, all symptoms of graymold of tomato plants were controlled by T. harzianum T-39 (I-952).

EXAMPLE 10

A composition of T. harzianum T-39 (I-952) was sprayed on strawberryfruits naturally infested with B. cinerea. Treated and non-treatedfruits were incubated in a humidity chamber. Table 9 shows that T-39successfully reduced gray mold.

EXAMPLE 11

Compositions of T. harzianum T-39 (I-952) were sprayed on cucumberplants in unheated greenhouses at various locations. Plots consisted ofat least 10 plants, repeated 5-6 times, in a randomized block design.Gray mold occurred on the fruits and stems at different rates accordingto the conditions in the specific greenhouse and the natural populationof B. cinerea. T. harzianum T-39 (I-952) was sprayed alone, in a tankmixture with another fungicide, or alternatively with another fungicide.Table 10 shows that compositions containing T harzianum (I-952)significantly reduced the incidence of the disease.

EXAMPLES 12-13

The objective of these tests was to determine if there is any effect onthe process of preparing wine made from grapes treated with compositionscontaining T. harzianum T-39 (I952). A preparation of T. harzianum T-39(I-952) was sprayed at a rate of 4 kg/ha on the grapes (cv. SauvinionBlanc) in vineyards located in Ortal (Golan Heights, Northern Israel).Spray was conducted in mid August, 1989, by a back sprayer to two rowsof vines, each 20 m long. Non-sprayed rows of vines, separated by 3 rowsof buffer rows, served as control. No fungicides were sprayed in theexperiment site, but all other treatments were carried out according tothe recommendations in the region. On Jan. 9, 1989 ten samples of 10 kggrapes were randomly sampled in the vineyard and transferred to thelaboratory. Grape juice was produced out of each sample of grapes. SO₂was added to the juice after production and 6 hours later yeasts andnutrients were added according to recommendations. The fermented juicewas incubated in 1 liter bottles with a pipe letting of CO₂ out from thesystem.

The Brix level (%) was measured with a Brix counter and the results areshown in Table 11. The population of yeast cells was counted by aheamocytometer and the results are shown in Table 12.

From these results it can be concluded that total soluble solids asmeasured by the Brix method did not differ between the control and thatstemming from grapes treated with T-39. Furthermore, while the initialmeasurements showed a drop in the yeast cell population, this was notstatistically significant and after 8 days the results were essentiallythe same. Therefore the use of T. harzianum T-39 (I-952) on grapes hasno significant effect on the production therefrom of ethanol. Finally,wine tasting revealed no difference in odor, color, taste and claritybetween wine made from the control juice and wine whose grapes weretreated with T. harzianum T-39 (I-952).

EXAMPLE 14

Conidia of T. harzianum T-39 (I-952) were sprayed on rose flowers.Flowers were then monitored for the level of T. harzianum populationover them during one week after spray. The level of T. harzianumpopulation was determined by washing the flowers in water containing0.001 M Tween-20 serial dilution of the wash water, and plating onTrichoderma selective medium. Colonies were counted after incubation for5 days at 20° C. The population level of T. harzianum did not dropdrastically during the week as shown in Table 13.

EXAMPLE 15

A composition of T. harzianum T-39 (I-952) was sprayed at a rate of 0.2%to 0.4% on strawberry plants in field plots (4 replicates of 10×1.6meters) arranged in randomized blocks and the results compared with theeffect of chemical fungicides. After four weeks the disease incidence onthe strawberries was reduced by T. harzianum T-39 (I-952) a rate similarto that by the fungicides, as shown in Table 14.

EXAMPLE 16

A composition of T. harzianum T-39 (I-952) was applied at a rate of 0.2%to 0.4% to carrots naturally infected by S. sclerotiorum. The carrotswere treated after harvest and incubated in a humidity chamber. Aftertwo weeks the disease severity of white rot was tested. It can be seenthat the white rot of carrots was reduced significantly by both rates ofT-39; but was not reduced by thiobendazole applied at the recommendedrate, as shown in Table 15.

EXAMPLE 17

A composition of T. harzianum T-39 (I-952) was sprayed on cucumberplants in a greenhouse. The population of T-39 was measured on theleaves and fruit as a factor of time. It can be seen from Table 16, thatthe biocontrol agent established itself on the canopy of the cucumberplants.

                  TABLE 1                                                         ______________________________________                                        Sensitivity Of T. harzianum T-39 (I-952)                                      To Pesticides In PDA.                                                         A. Highly inhibiting                                                                              Moderately inhibiting                                     agents.sup.a        agents.sup.b                                              ______________________________________                                        Vinclozolin         Diethofencarb                                             Iprodione           Polyoxin D                                                Carbendazim         Polyoxin B                                                Benomyl             Dichlofluanid                                             Carbendazim + diethofencarb                                                                       Thiram                                                    Chlorothalonil      CuSO.sub.4.5H.sub.2 O                                     Metomeclan          Diphenylamine                                             Terbuconazole       Folpet                                                    Procymidon          Tridemorph                                                Fluazinon           Bitertanol                                                Tebuconazole                                                                  Prochloraz                                                                    ______________________________________                                         .sup.a = Inhibition at a pesticide concentration of 2 ppm or less.            .sup.b = Inhibition at a pesticide concentration of 2-15 ppm.            

                  TABLE 2                                                         ______________________________________                                        Sensitivity Of T. harzianum T-39 (I-952)                                      To Pesticides In PDA.                                                         No Inhibition.sup.a                                                           ______________________________________                                        Dimethirimol  Methomyl                                                        Triforine     Triadimefon                                                     Dichloronitroaniline                                                                        Quinomethionate                                                 Bupirimate    Diniconazole                                                    Hexaconazole  Methidathion                                                    Miclobutanil  Copper oxychloride                                              Fenitrothion  Imazalil                                                        Phosphethyl A1                                                                              Metalaxil                                                       Propiconazole Oradizyl + Cymoxanil + Mancozeb                                 Azinphos methyl                                                                             Triadimenol                                                     Chloropyrifos Ditalimfos                                                      Mancozeb      Sulphur                                                         Endosulfan    Penconazole                                                     ______________________________________                                         .sup.a = Inhibition at a pesticide concentration of greater than 15 ppm. 

                  TABLE 3                                                         ______________________________________                                        Severity Of Gray Mold Disease In The                                          Presence Of Trichoderma spp. Isolates                                         Applied As Conidial Suspensions                                                            Percentage of Disease Incidence                                  Isolate Origin     Tomato   Pepper                                                                              Geranium                                                                              Rose                                ______________________________________                                        Control  --        100      100   100     100                                 T-39    Cucumber.sup.a                                                                            61      46     6      20                                  T-44    Soil        83      80    126     25                                  TOM     Soil        83      56    111     40                                  T-502   Soil        67      56    111     25                                  T-672   Soil       100      53     36     58                                  T-35    Soil       100      80     44     50                                  T-Y     Soil       100      60     36     57                                  T-164G  Cucumber.sup.a                                                                           100      80     92     40                                  T-180H  Soil       100      60    180     50                                  T-80    Soil       100      73    180     65                                  T-RCTI  Grapes/     78      80     17     65                                          France                                                                T-28    Soil        67      66     55     65                                  T-65G   Eggplant.sup.a                                                                           122      66     64     83                                  T-315   Soil       133      66    100     83                                  T-FOR   Soil        89      80    100     58                                  T-94    Soil       100      56    111     75                                  T-501   Soil        66      93     83     25                                  T-132G  Tomato     100      73    110     40                                  T-CW 10 Soil        89      100    72     83                                  T-GAM   Soil       100      68    127     108                                 T-GEN-12                                                                              Soil        88      80    154     100                                 T-33    Soil        96      86     50     100                                 T-177G  Cucumber.sup.a                                                                           100      86     62     60                                  T-55    Soil       100      86    100     200                                 T-199G  Grapes     100      100   100     163                                 T-59G   Grapes     100      73    100     125                                 T-133G  Grapes      68      73    130     100                                 T-191G  Tomato     100      75     72     100                                 T-192G  Eggplant.sup.a                                                                           100      80     50     63                                  ______________________________________                                         .sup.a = Greenhouse.                                                     

                                      TABLE 4                                     __________________________________________________________________________    Effect Of T. harzianum T-39 (I-952) And Iprodione                             Against Gray Mold In Wine Grapes.                                             Active        Spray                                                                              Carignan Variety in                                                                     Gamay in Chazay                                                                        Gamay                                   Ingredient                                                                              Dose.sup.a                                                                        Program.sup.c                                                                      Carcassonne                                                                             d'Azergnes                                                                             in Villefranch                          __________________________________________________________________________                       % Berries Infected                                                            22/3.sup.d                                                                         10/4.sup.e                                                                         14/4.sup.f                                                                             4/4.sup.g                                                                        21/4.sup.h                           Untreated          19.7 48.2 33.3     3.1                                                                              10.4                                 Iprodione 500 ABCD                    0.5                                                                              1.8                                            750 ABCD 5.0  3.3  14.5     0.6                                                                              3.3                                  T-39       4.sup.b                                                                          ADCD 5.0  18.4 20.0     2.8                                                                              7.0                                  Iprodione and T-39                                                                      500 ADCD           15.9     0.6                                                                              2.4                                             4.sup.b                                                            T-39 followed by                                                                         4  AB   2.0  11.0                                                  Iprodione 750 CD                                                              __________________________________________________________________________    .sup.a = gram active ingredient per hectare.                                  .sup.b = 4 kg/ha of formulation.                                              .sup.c = A = cap fall; B = Bunch Clos; C = Verairon; D = Pre-harvest          .sup.d = 22 days after treatment 3.                                           .sup.e = 10 days after treatment 4.                                           .sup.f = 14 days after treatment 4.                                           .sup.g = 4 days after treatment 4.                                            .sup.h = 21 days after treatment 4.                                           Location  Dates of Treatments                                                 Cascassonne                                                                             21.6.1989: 5.7.1989: 17.8.1989; 11.9.1989.                          Chazay d'Azerguer                                                                       14.6.1989; 4.7.1989;  3.8.1989; 22.8.1989.                          Villefranche                                                                            15.6.1989: 4.7.1989;  1.8.1989; 21.8.1989.                      

                  TABLE 5                                                         ______________________________________                                        Effect Of T. harzianum T-39 (I-952) On The                                    Incidence Of Gray Mold On Stems Of Rose Bushes                                                   Cumulative Number Of                                       Treatment          Infected Stems Per 10 Plants                               ______________________________________                                        Non-treated Control                                                                              10.8                                                       T-39 (4 g/l)       5.6                                                        Terbuconazole + Dichlo-                                                                          3.8                                                        fluanide                                                                      T-39 followed by Tebuconazole +                                                                  3.8                                                        Dichlofluanide                                                                Polyoxin B (1.0 g/1)                                                                             3.8                                                        ______________________________________                                    

                  TABLE 6                                                         ______________________________________                                        Effect Of Conidia Of T. harzianum T-39 (I-952) Sprayed                        On Rose Flowers Naturally Infested With B. Cinerea.sup.a                      Concentration of Conidia (per ml)                                                                  Disease Index.sup.b                                      ______________________________________                                        0                    2.7                                                      10.sup.6             2.0                                                      10.sup.7             1.0                                                      ______________________________________                                         .sup.a = After 6 days in a humidity chamber.                                  .sup.b = Key:                                                                 0 = No disease.                                                               5 = completely infected                                                  

                  TABLE 7                                                         ______________________________________                                        Effect Of T. harzianum T-39 (I-952) Sprayed in the                            Vinegard on Gray Mold of Table Grapes                                                    Infections per 10 Vines                                                         CV.                                                              Treatment    Barlinka.sup.a,b                                                                        CV. Shami.sup.a,b                                                                        Cu. Shami.sup.a,c                           ______________________________________                                        Untreated control                                                                          6.2       20.3       5.6                                         T-39 (4 g/l) 2.8       13.3       2.7                                         Folpet       1.8       --         --                                          Iprodione (0.5 g/l)                                                                        --         8.6       2.3                                         Diethofencarb +                                                                            --        11.3       0.3                                         Carbendazim (0.25 g/l                                                         each)                                                                         T-39 + Iprodione                                                                           --         3.0       1.3                                         T-39 alternated by a                                                                       --        11.0       3.0                                         mixture of Diethocarb                                                         and Carbendazim                                                               ______________________________________                                         .sup.a = Cultivar of grape.                                                   .sup.b = Tested in the vineyard.                                              .sup.c = Tested 7 days after harvest.                                    

                  TABLE 8                                                         ______________________________________                                        Effect Of T. harzianum T-39 (I-952) On                                        Tomato Plants In Greenhouses                                                               Fruit  Infected  Infected                                                                             Fruit Ghost                              Treatment    Rot.sup.a                                                                            Leaves.sup.a                                                                            Stems.sup.a                                                                          Spots.sup.b                              ______________________________________                                        Nontreated control                                                                         39.8   20.4      1.2    2.6                                      T-39 (4 g/l) 23.8   13.0      0.2    0.5                                      Iprodione (0.5 g/l)                                                                        15.0   4.6       0.2    0.3                                      ______________________________________                                         .sup.a = Number of infections per 10 plants.                                  .sup.b = Disease index:                                                       0 = Healthy fruit.                                                            5 = Fruit completely covered with spots.                                 

                  TABLE 9                                                         ______________________________________                                        Effect Of T. harzianum T-39 (I-952) On The                                    Post-Harvest Control Of Gray Mold In Strawberry                               Days of Incubation                                                                           Disease Index.sup.a                                            in Humidity Chamber                                                                          Non-treated Fruit                                                                          Treated Fruit                                     ______________________________________                                         9             3.0          1.6                                               11             3.5          2.4                                               13             4.6          2.8                                               ______________________________________                                         .sup.a = Disease Index:                                                       0 = Healthy.                                                                  5 = CompleteIy destroyed.                                                

                                      TABLE 10                                    __________________________________________________________________________    Effect Of T. harzianum T-39 (I952) On Infections of                           Cucumber Fruits And Stems In Various Locations In Israel.sup.a                                Disease Incidence As Number of Infections                                     Per 10 Plants                                                                 Ara.sup.b                                                                           Herut.sup.b                                                                       Gadish.sup.b                                                                        Ibtan.sup.b                                                                         Ahitu                                   Treatment       Fruit                                                                            Stem                                                                             Fruit                                                                             Fruit                                                                            Stem                                                                             Fruit                                                                            Stem                                                                             Stems                                   __________________________________________________________________________    Nontreated Control                                                                            33.3                                                                             12.3                                                                             174.7                                                                             15.7                                                                             12.0                                                                             34.3                                                                             48.0                                                                              3.75                                   Vinclozolin (0.5 g/l)                                                                         18.3                                                                             4.3                                                                              --  -- -- -- -- --                                      Iprodione (0.5 g/l)                                                                           -- -- 88.0                                                                              5.5                                                                              4.8                                                                              13.4                                                                             16.8                                                                             1.5                                     T-39 (2 g/l)    10.8                                                                             2.0                                                                              --  -- -- -- -- --                                      T-39 (4 g/l)    -- -- 14.1                                                                              3.8                                                                              5.5                                                                              15.0                                                                             24.0                                                                             2.0                                     T-39 (4 g/l)    -- -- 15.0                                                                              2.8                                                                              1.5                                                                              15.4                                                                             15.3                                                                             0.2                                     mixed with Iprodione (0.5 g/l)                                                T-39 (4 g/l)    -- -- --  -- -- 12.5                                                                             22.0                                                                             --                                      alternated by Iprodione (0.5 g/l)                                             __________________________________________________________________________     .sup.a = Sprayed at a volume of 1000 l/ha.                                    .sup.b = Location in Israel.                                             

                  TABLE 11                                                        ______________________________________                                        Effect of T. harzianum T-39 (I-952) On The Brix Level                         of Grape Juice Made From Grapes Treated With T-39                             Treatment  Days of Incubation                                                 in Vineyard                                                                              1         3      8      11   17                                    ______________________________________                                        Control    16.0      11.8   6.4    6.3  6.3                                   Trichoderma T-39                                                                         15.5      11.1   6.2    6.2  6.2                                   (I-952)                                                                       ______________________________________                                         Differences between treatments at each date were statistically not            significant, according to Duncan's Multiple Range Test (.sub.-- P = 0.05)

                  TABLE 12                                                        ______________________________________                                        Effect of T. harzianum T-39 (I-952) On The                                    Number of Yeast Cells In Grape Juice                                          Made From Grapes Treated With T-39.                                                      Number of yeast cells (× 10.sup.4)                           Treatment  Days of Incubation                                                 in vineyard                                                                              1        3       8      11   17                                    ______________________________________                                        Control    9280     12520   6000   17.8 38.2                                  T. harzianum T-39                                                                        6960     10300   1802   90.9 47.7                                  ______________________________________                                         Differences between treatments at each date were not statistically            significant, according to Duncan's Multiple Range Test (.sub.-- P = 0.05)

                  TABLE 13                                                        ______________________________________                                        Population of T. harzianum T-39 (I-952) On Rose                               Flowers Treated With Conidia of the Biocontrol Agent                                     Level of Initial Population                                        Days of Incubation                                                                         0     1          2      3                                        ______________________________________                                        1            0     9.0 × 10.sup.5                                                                     2.7 × 10.sup.7                                                                 1.6 × 10.sup.8                     3            0     5.2 × 10.sup.5                                                                     2.3 × 10.sup.7                                                                 4.0 × 10.sup.8                     7            0     2.0 × 10.sup.5                                                                     0.3 × 10.sup.7                                                                 0.8 × 10.sup.8                     ______________________________________                                    

                  TABLE 14                                                        ______________________________________                                        Effect of T. harzianum T-39 (I-952) on Strawberry                             Gray Mold in Naturally Infested Field.sup.a                                   Treatment           Infected Fruits/10 m row                                  ______________________________________                                        Control             11.25                                                     T-39 (0.2%)         6.75                                                      T-39 (0.4%)         4.50                                                      Folpet (0.25%)      4.0                                                       Carbendazin + Dithiofencarb (0.1%)                                                                3.75                                                      ______________________________________                                         .sup.a Spraying was carried out four weeks prior to disease assessment   

                  TABLE 15                                                        ______________________________________                                        Effect of T. harzianum T-39 (I-952) on the Severity of                        S. sclerotiorum Applied to Carrots After Picking                              Treatment        Disease Index.sup.a,b                                        ______________________________________                                        Control          0.714                                                        T-39 (0.2%)      0.536                                                        T-39 (0.4%)      0.427                                                        Thiabendazol (0.1%)                                                                            0.821                                                        ______________________________________                                         .sup.a Two weeks after treatment                                              .sup.b Key:                                                                   0 = No disease                                                                5 = Completely destroyed carrots                                         

                  TABLE 16                                                        ______________________________________                                        Population Level of T. harzianum T-39 (I-952) on                              Leaves and Fruit of Cucumber in a Green House                                 Sampling Time                                                                            Propagules of T. harzianum                                         (Days after                                                                              Per Leaf       Per Fruit                                           Application)                                                                             Untreated Treated  Untreated                                                                             Treated                                 ______________________________________                                         0          54         20       0        0                                    28          232       9000     210      300                                   21         2300      450000   1500    350000                                  ______________________________________                                    

We claim:
 1. A biologically pure, stable culture of Trichodermaharzianum having all the identifying characteristics of Trichodermaharzianum I-952, or a mutant derived therefrom which retains thebioinhibitory properties of the parent strain I-952.
 2. The culture ofclaim 1, wherein said mutant retains the property of resistance to apesticide capable of retarding the growth of other fungi or pests. 3.The culture of claim 2, wherein the pesticide is a fungicide.
 4. Theculture of claim 3, wherein the fungicide is selected from the groupconsisting of folpet and dicarboximide fungicides.
 5. The culture ofclaim 5, wherein the dicarboximide fungicides are selected from thegroup consisting of iprodione and vinclozolin.
 6. A biocontrolcomposition comprising an effective amount for inhibitory activityagainst at least one of B. cinera and S. sclerotiorum, of the culture ofa biologically pure, stable culture of Trichoderma harzianum having allthe identifying characteristics of Trichoderma harzianum I-952, or amutant derived therefrom which retains the bioinhibitory properties ofthe parent strain I-952, and a suitable agronomically acceptablecarrier.
 7. The biocontrol composition of claim 6, wherein theconcentration of said strain I-952, or the mutant derived therefore,contained in the culture is at least 10⁵ cells per gram of thecomposition.
 8. The biocontrol composition of claim 6, wherein saidstrain I-952, or the mutant derived therefrom, contained in the cultureis present in the form of conidia, chlamydospores or hyphal fragments ormixtures of these types of cells.
 9. The biocontrol composition of claim6, wherein the carrier includes a food base for said strain I-952, orthe mutant derived therefrom, contained in the culture.
 10. Thebiocontrol composition of claim 6, further comprising a pesticide. 11.The biocontrol composition of claim 10, wherein the pesticide is afungicide.
 12. The biocontrol composition of claim 11, wherein thefungicide is selected from the group consisting of folpet anddicarboximide fungicides.
 13. The biocontrol composition of claim 12,wherein the dicarboximide fungicides are selected from the groupconsisting of iprodione and vinclozolin.
 14. The biocontrol compositionof claim 6, wherein said carrier is selected from the group consistingof diatomaceous earths and celite.